In the field of catalysis, and also, for example, in the field of adsorption or adsorption processes, providing novel framework topologies with novel pore architectures plays a crucial role in the development of catalysts, catalyst components, and catalyst support materials displaying novel reactivity and/or improved performance. In this respect, the condensation of layered silicates into new zeolitic frameworks via topotactic procedures is intensively investigated in past and present research.
Thus, synthesis and characterization of products resulting from the reaction of selected layered silicates having MWW-type, FER-type and CDO-type layers with diethoxy dimethyl silane is disclosed in P. Wu et al.; J. Am. Chem. Soc., 130, 2008, pp. 8178-8187. In particular, silylation products described therein are obtained by a method of refluxing specific layered silicate precursors in nitric acid followed by a calcinations procedure. As a result of said procedure, it is possible to obtain a pillared silicate compound having a layered silicate structure, wherein the silicate layers are covalently bound to one another via bridging silicon atoms thus forming a three-dimensional framework.
As further discussed in J. Ruan et al.; Chem. Mater., 21, 2009, pp. 2904-2911, with respect to the alkoxysilylation of an FER lamellar precursor (PREFER), calcinations of the pillared silicate product leads to further reaction of the bridging silicon moieties with one another, such that these become bridged to one another via bridging oxygen atoms. Furthermore, Ruan et al. expand the alkoxysilylation methodology to include the use of hydrothermal methods for inducing silylation.
Accordingly, pillared silicate compounds comprising a layered silicate structure, wherein silicate layers of the silicate structure are bridged by silicon moieties are known in the art. Furthermore, it is known that calcination of said pillared silicate compounds leads to further bridging via condensation of bridging silicon moieties thus forming further Si—O—Si bridging in the interlayer space. Consequently, it is known from the prior art that covalent pillaring of layered silicate compounds may be achieved by an alkoxysilylation procedure, thus affording three-dimensional zeolitic materials.
It would desirable to provide novel pillared silicate compounds displaying novel and improved properties, in particular with respect to the physical properties and catalytic activity thereof.